1. Field of the Invention
The present invention relates to a technique for extracting piled objects.
2. Description of the Related Art
Japanese Patent Nos. 4087874 and 4199264, for example, discuss techniques for, when extracting piled workpieces in order by capturing an image of the workpieces with a camera, estimating the position and the orientation of each workpiece based on the captured image, and grasping a workpiece with a robot, quickly and correctly estimating the position and the orientation of each workpiece to perform the work.
The technique discussed in Japanese Patent No. 4087874 is directed to improving estimation accuracy by placing a restriction condition on a size estimation to be performed from the next time onward by using an estimation result of the size of the extracted workpiece.
The technique discussed in Japanese Patent No. 4199264 is directed to increasing speed by determining whether a piled state of workpieces has changed due to an extraction operation, and if it is determined that the piled state has not changed around the workpiece to be extracted next, not perform image capturing when extracting the next workpiece.
Thus, to extract workpieces in order from piled workpieces, the position and the orientation of the workpieces have to be estimated. However, from an operation efficiency perspective, the time required for that estimation is desirable to be short.
The technique discussed in Japanese Patent No. 4087874 places a restriction on the size estimation to be performed from the next time onward using a size estimation result of the workpiece extracted this time. Therefore, there needs to be some kind of association between the size of the workpiece extracted this time and the size of the workpiece to be extracted next time.
However, when considering estimation of the position and the orientation of piled workpieces, the relationship between the position and the orientation of a workpiece that is extracted first and the position and the orientation of the workpieces extracted second or later is tenuous. Therefore, it is difficult to employ the technique discussed in Japanese Patent No. 4087874.
Further, the technique discussed in Japanese Patent No. 4199264 does not consider increasing speed when the piled state has changed.